Add missing const to CPDF_Stream::InitStream()

core/fpdfapi/fpdf_parser/include/cpdf_stream.h

 // Copyright 2016 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef CORE_FPDFAPI_FPDF_PARSER_INCLUDE_CPDF_STREAM_H_
 #define CORE_FPDFAPI_FPDF_PARSER_INCLUDE_CPDF_STREAM_H_
 
 #include "core/fpdfapi/fpdf_parser/include/cpdf_dictionary.h"
@@ skipping 14 matching lines @@
   const CPDF_Stream* AsStream() const override;
 
   uint32_t GetRawSize() const { return m_dwSize; }
   uint8_t* GetRawData() const { return m_pDataBuf; }
 
   void SetData(const uint8_t* pData,
                uint32_t size,
                FX_BOOL bCompressed,
                FX_BOOL bKeepBuf);
 
-  void InitStream(uint8_t* pData, uint32_t size, CPDF_Dictionary* pDict);
+  void InitStream(const uint8_t* pData, uint32_t size, CPDF_Dictionary* pDict);
   void InitStreamFromFile(IFX_FileRead* pFile, CPDF_Dictionary* pDict);
 
   FX_BOOL ReadRawData(FX_FILESIZE start_pos,
                       uint8_t* pBuf,
                       uint32_t buf_size) const;
 
   bool IsMemoryBased() const { return m_GenNum == kMemoryBasedGenNum; }
 
  protected:
   static const uint32_t kMemoryBasedGenNum = (uint32_t)-1;
 
   ~CPDF_Stream() override;
 
   void InitStreamInternal(CPDF_Dictionary* pDict);
 
   CPDF_Dictionary* m_pDict;
   uint32_t m_dwSize;
   uint32_t m_GenNum;
 
   union {
     uint8_t* m_pDataBuf;
     IFX_FileRead* m_pFile;
   };
 };
 
 #endif  // CORE_FPDFAPI_FPDF_PARSER_INCLUDE_CPDF_STREAM_H_